Method and system for wakeup trigger by out-of-band communication

ABSTRACT

A method at a wireless station for receiving an out-of-band wakeup trigger, the method including receiving, at the wireless station, a message from an access point, the message providing an indication that the access point supports out-of-band signaling; associating with the access point over a first radio technology; establishing a connection with the access point using a second radio technology; entering a sleep state for a radio using the first radio technology; and upon receiving a wakeup trigger over the connection using the second radio technology, waking up the radio for the first radio technology for communication with the access point.

FIELD OF THE DISCLOSURE

The present disclosure relates to wireless local area network (WLAN)technology and in particular relates to WLAN technology having reducedlatency and power consumption.

BACKGROUND

One of the challenges with using WLAN technology, for example forInternet of Things (IoT) communications, is balancing networkconnectivity with battery conservation. If a WLAN radio is always on fora wireless station (STA), then there is low latency in exchanging data,but power consumption can be significant. This may be problematic forbattery powered wireless stations.

Conversely, the radio can be turned off for a duty cycle to reduce powerconsumption. However, the longer the radio is off, the higher thelatency. In particular, in communications with longer duty cycles, oftenthe wireless station does not communicate with an access point (AP) foran extended period, making it impossible to transmit data from the AP tothe wireless station. This may be problematic for wireless stations thatneed data with low latency.

Further, with the radio being off for a long period, associationsbetween the STA and AP may be lost, and the overhead of establishing ormaintaining network connectivity with that access point could be a keycontributor to power consumption.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be better understood with reference to thedrawings, in which:

FIG. 1 is a block diagram showing an example network architecture with asingle access point;

FIG. 2 is a data flow diagram showing communications between a wirelessstation and an access point, where each has an out-of-band radio;

FIG. 3 is a block diagram of an example wakeup radio element for use ina management frame;

FIG. 4 is a block diagram of an example wakeup radio capabilities fieldwithin the wakeup radio element of FIG. 3;

FIG. 5 is a block diagram showing a process for an access point to enterand leave a Sleep state;

FIG. 6 is a block diagram of an example wakeup radio capabilities fieldwithin the wakeup radio element of FIG. 3 having a base service set(BSS) transition bit;

FIG. 7 is a block diagram of a simplified electronic device capable ofbeing used with the methods and systems herein according to oneembodiment; and

FIG. 8 is a block diagram of a mobile device according to oneembodiment.

DETAILED DESCRIPTION OF THE DRAWINGS

The present disclosure provides a method at a wireless station forreceiving an out-of-band wakeup trigger, the method comprising:receiving, at the wireless station, a message from an access point, themessage providing an indication that the access point supportsout-of-band signaling; associating with the access point over a firstradio technology; establishing a connection with the access point usinga second radio technology; entering a sleep state for a radio using thefirst radio technology; and upon receiving a wakeup trigger over theconnection using the second radio technology, waking up the radio forthe first radio technology for communication with the access point.

The present disclosure further provides a wireless station configuredfor receiving an out-of-band wakeup trigger, the wireless stationcomprising: a processor; and a communications subsystem, wherein thewireless station is configured to: receive a message from an accesspoint, the message providing an indication that the access pointsupports out-of-band signaling; associate with the access point over afirst radio technology; establish a connection with the access pointusing a second radio technology; enter a sleep state for a radio usingthe first radio technology; and upon receiving a wakeup trigger over theconnection using the second radio technology, wake up the radio for thefirst radio technology for communication with the access point.

The present disclosure further provides a computer readable medium forstoring program instructions for receiving an out-of-band wakeuptrigger, the program instructions, when executed by a processor of awireless station, cause the wireless station to: receive a message froman access point, the message providing an indication that the accesspoint supports out-of-band signaling; associate with the access pointover a first radio technology; establish a connection with the accesspoint using a second radio technology; enter a sleep state for a radiousing the first radio technology; and upon receiving a wakeup triggerover the connection using the second radio technology, wake up the radiofor the first radio technology for communication with the access point.

The present disclosure further provides a method at an access point, themethod comprising: transmitting, from the access point, a message, themessage providing an indication that the access point supportsout-of-band signaling; associating the access point with at least onewireless station over a first radio technology, the associatingcomprising receiving an indication that the at least one wirelessstation supports out-of-band signaling; establishing a connection withthe at least one wireless station to the access point using a secondradio technology; receiving an indication that the at least one wirelessstation is entering a sleep state for a radio using the first radiotechnology; receiving data for the at least one wireless station;buffering the data; sending a wakeup trigger over the connection usingthe second radio technology; receiving a signal over the first radiotechnology that the at least one wireless station is awake; and sendingthe buffered data to the at least one wireless station using the firstradio technology.

Current power-saving techniques applied to WLAN technology typicallysacrifice latency for power consumption. IoT devices may, in someembodiments, be battery powered and therefore have limited power. Inthis regard, it is desirable to have lower power consumptioncommunications while maintaining low latency communications.

One WLAN technology that is used for illustrative purposes in thepresent disclosure is the Institute of Electrical and ElectronicsEngineers (IEEE) 802.11 standard. In some embodiments this standard isalso known as Wi-Fi. However, the 802.11 standard is only provided as anexample, and other WLAN technologies are possible.

Numerous power saving techniques are defined in the IEEE 802.11standard. However, these rely on legacy physical or medium accesscontrol (MAC) layer behaviors. These behaviors require a device, whileconnected, to remain synchronized with the peer device or Access Point.This is done by waking up to receive beacon frames, which aretransmitted periodically. For example, in one embodiment the beaconframes may be transmitted every several hundred milliseconds.

Thus, under the IEEE 802.11 standard, an STA has the capability tooperate in one of two power states: Doze and Awake. In the Doze state,the STA has the capability of turning off its radio for a predeterminedamount of time. Signaling in the WLAN operating channel allows STAs tocommunicate their current power-save state. However, by turning off theradio for a specific amount of time, latency is introduced forcommunications in the network. Specifically, download communications tothe STA will need to wait until the STA next wakes up (e.g. enters theAwake state).

In another power savings technique, a device that infrequentlycommunicates with the network may disconnect from the network, but isrequired to discover, authenticate, and associate to a network beforeresuming communications. Such device may be unreachable for downlinkcommunications while disconnected.

Specifically, for applications that involve longer duty cycles, thedevice may periodically associate to a network to communicateinformation and then disassociate with the network after communicationis complete. However, the power consumption overhead of associating anddisassociating to an access point can exceed the power consumption incommunicating with the network. Thus the power optimization comes at acost of the overhead of connecting and disconnecting, as well as thelatency introduced for downlink communications, which can only be pushedwhen the device comes back on line.

Other techniques, including unscheduled automatic power-save delivery(U-APSD), basic service set (BSS) Max Idle Period Management, andDirected Multicast Service, also optimize power at a cost of highlatency for downlink traffic.

All of these techniques consume power and introduce latency.

Further, in instances where mobility is required, when using the abovepower saving techniques the STA may move out of range of the AP while ina Doze state or not communicating with the network. The STA may movebetween APs as it travels around.

By moving out of range, the STA will need to rediscover a new AP when itwakes up (e.g. enters the Awake state) and fails to receive a beaconfrom the AP it was originally connected to. This can both increase powerconsumption and latency.

Thus, in accordance with the embodiments of the present disclosure, anout-of-band trigger is provided for a wakeup signal to a WLAN radio. Theout-of-band signal is transmitted using a low power radio communication.In one embodiment the low power radio communication has similartransmission distance to the WLAN but with lower power consumption.Examples of such out-of-band radio technologies may include, but are notlimited to, Bluetooth™ Low Energy (BLE), IEEE 802.15 technologyincluding ZigBee™, among other options. The low power out-of-bandcommunication is described below using Bluetooth Low Energy forillustration purposes, but the present disclosure is not limited to thatparticular technology.

In the embodiments described below, the state machines of the low powerout-of-band communications and the WLAN are linked to allow the WLANstate machine to remain “associated” even when the WLAN radio is turnedoff and in a Sleep state.

Reference is now made to FIG. 1, which shows an example environment forthe operation of an access point and various wireless stations. Thestations may be either mobile or fixed.

In particular, the example of FIG. 1 shows wireless stations 110, 112,and 114. In many cases, stations 110, 112 and 114 may be batteryoperated, and therefore have limited power resources.

In one embodiment, wireless stations 110, 112 and 114 can be any devicecapable of connecting to an access point 120. In other embodiments,wireless stations can connect to each other, for example in independentBSS (IBSS) networks or mesh networks. Examples can include mobiledevices such as smartphones or cellular telephones. Examples can furtherinclude fixed or mobile devices, such as internet of things devices,home automation devices, medical equipment in hospital or homeenvironments, inventory tracking devices, environmental monitoringdevices, energy management devices, infrastructure management devices,vehicles or devices for vehicles, fixed electronic devices, amongothers.

Wireless stations 110, 112 and 114 connect to an access point 120.Access point 120 may then connect, for example, through the internet 130to one or more servers 140. Servers 140 may, for example, store data orprovide coordination for one or more of stations 110, 112 and 114.

The architecture of FIG. 1 is merely an example of one simplifiedarchitecture. Other architectures are within the scope of the presentdisclosure.

In most WLAN solutions presently, both wireless stations 110, 112 or114, as well as access point 120, are built using hardware that hasBluetooth™ capabilities. The solutions presented herein thereforeleverage Bluetooth™ low energy radio and protocols for signaling forwakeup radio.

Reference is now made to FIG. 2, which shows a data flow diagram forcommunications between a wireless station and an access point. Each ofthe wireless station and access point have a second, low energy radiofor transmission of beacon information for the first radio technologyand for use as wakeup radio.

In particular, a wireless station 110 communicates with an access point120. Wireless station 110 includes a first radio technology radio, whichin the example of FIG. 2 is a WLAN radio 210. Wireless station 110further includes a second radio technology radio, which in the exampleof FIG. 2 is a Bluetooth™ Low Energy radio 212.

Similarly, access point 120 includes first and second radio accesstechnology radios, which in the example of FIG. 2 include a WLAN radio220 and a Bluetooth™ Low Energy radio 222.

Prior to any association between the wireless station 110 and the accesspoint 120, the access point is transmitting repeated beacon frames,shown by message 230.

When station 110 receives a beacon frame 230, it may initiate adiscovery and association procedure, as shown by arrow 240 in theembodiment of FIG. 2.

In accordance with the present disclosure, the wireless station 110 isconfigured for wakeup radio (WUR) using out-of-band communications andtherefore may be referred to as a WUR-STA.

In one or both of the beacon frame 230 or in probe response frames sentduring the association procedure shown at arrow 240, the AP mayadvertise wakeup radio capabilities. A wakeup radio non-AP STA (WUR-STA)that recognizes these AP capabilities, may associate to the AP assertingits own wakeup radio capabilities.

For example, an STA, including AP or non-AP STAs, may communicate itsWUR capabilities with other STAs using a wakeup radio element in an802.11 management frame. The wakeup radio element is transmitted by awakeup radio STA, for example in a probe request, an associationrequest, a re-association request and/or a generic advertisement service(GAS) frame such as an access network query protocol (ANQP) frame.

The wakeup radio element is transmitted by an AP in the beacon, proberesponse, association response, re-association response and/or ANQPframe.

Reference is now made to FIG. 3, which shows an example wakeup radioelement. In the example of FIG. 3, a wakeup radio element includes threeoctets. A first octet 310 provides an element identifier. A second octet312 provides a length and a third octet 314 provides wakeup radiocapabilities.

The element identifier field 310 is set to the wakeup radio capabilitieselement value or an equivalent WUR ANQP-element information identifier.

The link element field 312 is set to the length of the element (3octets).

The wakeup radio capabilities field 314 may, for example, be an elementas described in FIG. 4. Specifically, the wakeup radio capabilitiesfield 314 is a single octet which includes a plurality of bit fields.

A first bit field is a wakeup radio enabled bit field 412, which in theexample of FIG. 4 is a single bit. The wakeup radio enabled bitindicates that wakeup radio features are enabled on the STA.

Octet 314 further includes a Bluetooth™ Low Energy beacon enabled field414. Field 414, when set to one on a STA, indicates that the STAsupports Bluetooth low energy for wakeup radio.

An AP Sleep state field 416 in octet 314 comprises a single bit which isset to one by an AP if the AP is capable of moving into a Sleep state.This bit would be set to a zero by a WUR STA.

In the example of FIG. 4, the next four bits in octet 314 include the APSleep state count field 418. If the bit in field 416 is set to 1, thenthe value provided in field 418 indicates the number of Target BeaconTransmission Time (TBTT) intervals that an AP will remain in the Awakestate before transitioning to a Sleep state. The AP Sleep state countfield is updated on each beacon transmission until the AP enters theSleep state. If the AP remains awake, the AP Sleep state count field isset to 0. Further, in the case of an STA-STA connection, the STA in anon-infrastructure connection could use the AP Sleep state count field418 to indicate when it will enter the Sleep state.

The remaining bit field 420 is a single reserved bit.

Thus, wake-up radio capabilities for both the AP and WUR STA can beprovided in either or both of the beacon frames 230 and during discoveryand association 240.

Referring again to FIG. 2, in parallel with associating to the AP, (orfollowing the association to the AP), the WUR STA discovers andestablishes a BLE connection to the AP in one embodiment. In some cases,BLE discovery could also be achieved or facilitated using WLAN frames.For example, BLE discovery information such as the Bluetooth™ MACaddress of the AP may be exchanged using WLAN frames at the time of theassociation.

Once the WUR-STA associates to the AP 120, the WUR-STA and the AP mayalso negotiate out-of-band signaling using the Bluetooth™ Low Energy. Inone embodiment the WLAN association request/response from arrow 240 mayinclude information for the out-of-band signaling.

As described below, the BLE connection is used to synchronize the WURSTA with the AP while the WUR STA is in a WLAN Sleep state. The Sleepstate is defined as a new state in IEEE 802.11 which is only supportedon WUR STAs when WUR is enabled. The Sleep state is different from theDoze and Awake states currently defined in IEEE 802.11.

Thus, in FIG. 2, if the AP BLE 222 radio is off, the AP 120 may enableits BLE radio through a signal 242. The BLE radio 222 may for example beoff if wireless station 110 is the first WUR-STA that associates withthe AP 120.

Similarly, the if the BLE radio 212 on station 110 is off, it may beenabled using a signal 244.

Subsequently, a BLE connection 246 may be established. The AP 120enables the BLE General Access Profile (GAP) as described below, andbegins to broadcast BLE beacon frames and responses to BLE scan requestframes.

Upon successful BLE connection, the station 110 may signal that it isgoing into a Sleep state, as shown by arrow 250. Specifically, in oneembodiment station 110 uses a unicast frame to signal to AP 120 a statetransition from either the Awake or Doze state to the Sleep state. Suchunicast frame could be a data frame, control frame or management framein various embodiments.

The WUR STA remains synchronized with the AP over the BLE link.Specifically, BLE handshakes 252 and 254 could be used to provide beaconinformation for the WLAN over the BLE connection. The BLE handshakes cancontinue periodically while the devices are connected but the WLAN radio210 is turned off.

Under certain conditions, the AP may send an Open SystemsInterconnection (OSI) layer 2 or layer 3 signaling, such as AddressResolution Protocol (ARP), Dynamic Host Configuration Protocol (DHCP),or possibly multicast Domain Name System (mDNS), or other similarinformation over the Bluetooth link.

The STAs use the active BLE connection when at least the STA is in theSleep state. When a trigger condition arises, such as a reception of aframe for the WUR-STA at the AP or a condition that requires the WUR STAto move to an Awake state, either the AP or the STA notifies its peerover the BLE link to trigger a transition from the Sleep state to anAwake state. The STAs may then resume communications while in the Awakestate.

As seen in FIG. 2, a trigger condition arises with traffic arrival 260at the AP 120. The traffic arrival 260 may trigger the WLAN radio 220,which then signals to the BLE radio, 222 as shown by message 262.

For example, the AP may receive such traffic from a cellular network ina mobile hotspot, or over Ethernet/cable/DSL/fiber backhaul, among otheroptions. The frame that is received may be addressed to one of theassociated WUR STAs.

The BLE radio 222 may then signal to the station 110 that the traffic isavailable, as shown by message 264.

The station 110 then transitions from the Sleep to Doze state over theIEEE 802.11 link and signals to the AP to deliver the frame.Specifically, the station 110 may, utilizing its WLAN radio 210, signalto the WLAN radio 220 of access point 120 that it is an Awake or Dozestate. This is shown, for example, by message 270.

Upon the station 110 awaking its WLAN radio 210, any buffered traffic atthe access point 120 may be delivered, as shown by message 280.

For uplink traffic from station 110 to AP 120, when the station 110 hasdata to communicate it may also provide a message directly from the WLANradio 210 to the access point 120, assuming that the access point isawake. Thus, if the access point is in an Awake state, BLE connectionsignaling may not be needed for uplink traffic.

Subsequently, if station 110 and access point 120 remain associated thena transition may either be made back to the Bluetooth wakeup radio. Forexample, after a threshold time period after the last buffered data isdelivered, the wireless station 110 may again send message 250 to moveinto a Sleep state.

In other embodiments, a disconnection may occur between the station 110and access point 120. For example, this may occur is the station and APmove out of range of each other. Such disconnection is shown, forexample, in the embodiment of FIG. 2 with arrows 290 and 292 showingdisconnection of the WLAN radio and the Bluetooth™ radio respectfully.

AP Sleep State

While the embodiments described below deal with the AP moving into andout of a Sleep state, in other embodiments, such as for IBSS or meshnetworks, the functionality described below could be used fornon-infrastructure STAs as well.

In some embodiments, it may be desirable for an AP to move into a Sleepstate and turn off its WLAN radio. Communication with wireless stationscould still be made using a BLE radio, as described above. For example,if the AP is a battery operated device, it may wish to conserve batterypower.

Reference is now made to FIG. 5, which shows a process at an AP fortransitioning to a Sleep state and an Awake state.

The process of FIG. 5 starts at block 510 and proceeds to block 520 inwhich a check is made to determine whether all STAs serviced by the APare WUR-STAs. If not, the process remains in an Awake state, as shown byblock 522, and the process ends at block 524.

Conversely, if the access point is going to sleep and all of thestations that it services are WUR STAs, then the AP may use agroup-addressed frame to signal the state transition from the Awake tothe Sleep state, shown by block 530. Such group addressed frame couldinclude management, data or control frames.

The signaling could be done in a number of ways. In a first embodiment,the signal may define a new control frame to signal the state change.

In a further embodiment, the signaling uses a frame control field tosignal the state change in either a data frame or a management frame.For example, this may be done by setting both the Power-save (PS) bitfield and the More Data bit field to 1 in the same frame.

In still a further embodiment, a new management frame may be defined ora new format to the Quality of Service (QoS) Null data or Null dataframe may be used to signal the state change.

After successfully transmitting the frame, the AP sets the AP Sleepstate count field to the number of TBTTs before entering the Sleepstate, as shown by block 532. The AP decrements the AP Sleep state countfield in block 534 and enters Sleep state at block 536 once the countdecrements from 1.

During the Sleep state, the AP maintains all BSS states and properties.

The access point may monitor the Sleep state of the associated WUR STAsand remain synchronized.

A trigger condition exists as shown at block 540, for example, whentraffic needs to be sent or received. The AP may transition to an Awakestate, shown at block 542, and send a notification at block 544 over theBLE link triggering the STAs WLAN radio to wake up. The AP continues tobuffer traffic until the STA wakes up.

When the AP transitions from a Sleep state to an Awake state, it resumesbeacon frames and treats associated WUR STAs as if they are in a Dozestate.

In some embodiments, the AP may transition from a Sleep state to anAwake state in response to an associated WUR STA sending a trigger towake up using the BLE. This would occur when the STA has a frame totransmit to the AP.

The AP may also transition from the Sleep state to the Awake state inresponse to receiving a frame from the backhaul network. For example,the AP may receive such traffic from a cellular network in a mobilehotspot, or over ethernet/cable/DSL/fiber backhaul, among other options.The frame that is received may be addressed to one of the associated WURSTAs. In this case the AP wakes up and subsequently sends the triggerframe over the BLE to wake up the WUR STA. The WUR STA then transitionsfrom the Sleep to Doze state over the IEEE 802.11 link and signals tothe AP to deliver the frame.

In other cases, trigger conditions may be other event based triggers.For example, if a door is opened, a motion sensor is tripped in a homealarm system and the AP or STA may need to move from a Sleep to an AwakeState. In other examples, a time of day may be a trigger. Other optionsare possible.

Under certain conditions, the AP may send an OSI layer 2 or layer 3signaling, such as Address Resolution Protocol (ARP), Dynamic HostConfiguration Protocol (DHCP), or possibly multicast Domain Name System(mDNS), or other similar information over the Bluetooth link.

For a WUR-STA interacting with the AP, the WUR STA may monitor the Awakestate of the AP until it receives a group-addressed trigger frameindicating that the AP is going into a Sleep state. The WUR STA thenmonitors the AP Sleep state count and enters the Sleep state when the APenters the Sleep state. During the Sleep state, the WUR STA maintainssynchronization with the AP using the BLE link. When triggering toresume BSS communications, the WUR STA transitions from a Sleep state toa Doze state, and then sends a power-save trigger frame to the AP toresume communications.

Under certain conditions, the STA may send OSI layer 2 or layer 3signaling, such as ARP, DHCP, or possibly mDNS, or other similarinformation over the WUR link.

Bluetooth™ Behavior

With regard to the Bluetooth™ functionality in the above-describedembodiments, in one example the WUR STA behaves as a scanner forBluetooth™ functionality and the AP behaves as the advertiser. If twoWUR STAs are communicating, the STAs could negotiate which one becomesthe scanner, or the determination could be made based on a generatedintent value, MAC address value, among other options.

The combined connection process, in one embodiment is as follows.

First, the WUR STA may discover and Associate to the AP over WLAN.

Next, the AP enables BLE Beacons advertising WUR connectivity.

Next, the WUR STA scans for the AP over BLE after it successfullyassociates.

The WUR STA then discovers the AP over the BLE and initiates a BLEconnection.

The WUR STA and the AP then maintain the BLE connection while the WURSTA is in its Sleep state.

When buffered frames are available, at least two mechanisms areavailable to advertise the buffered frames to the WUR STA. In a firstembodiment, the AP may use an indication in the BLE Beacon to the WURSTA which would trigger the WUR STA to wake-up. This may be used, forexample, in non-latency sensitive embodiments. When the WUR STA receivesthe trigger that there is buffered traffic, it may resume communicationover the WLAN after a period of time after receiving the BLE Beacons inorder to receive non-latency sensitive data.

In a further embodiment, the AP may send a BLE Data frame to the WUR STAto trigger the STA to resume communications over the WLAN link. In thisembodiment, the WUR STA may resume communications over WLAN immediatelyin response to the BLE Data frame.

In accordance with one embodiment of the present disclosure, theBluetooth low energy uses a General Access Profile (GAP) to controladvertisement and connectivity. The WUR STA acts as a peripheral devicewhile the access point access is a central device. As will beappreciated by those in the art, the GAP defines the general topology ofthe BLE network stack.

Further, a General Attributes Profile (GATT) is defined to allow the APinfrastructure and the WUR STA to exchange information over the BLElink. In accordance with the Bluetooth™ specifications, a GeneralAttributes Profile (GATT) describes a use case, roles and generalbehaviors based on GATT functionalities. Services are collections ofcharacteristics and relationships to other services that encapsulate thebehavior of part of a device. GATT data is used to define the way thattwo Bluetooth low energy devices send and receive standard messages.

In the present embodiments, the GATT profile defines the advertisementfor Bluetooth low energy service discovery, and defines signaling forWUR over the BLE link between the devices.

The WUR STA associates to a WLAN AP over the WLAN link and searches forthe same AP over Bluetooth by scanning for the WLAN AP corresponding BLEbeacon. Once the BLE beacon has been discovered, the WUR STA thenestablishes a connection to the AP over BLE, using the WUR GATT profilein one embodiment. Alternatively, an existing profile with datacustomized to support WUR may be used.

The STA discovers and connects to the AP over the BLE link through theAP advertising the service instance for notifications in BLE beacons,along with a combination of the Basic Service Set Identification(BSSID), Service Set Identification (SSID), or any other identifierincluded in the WUR information over the WLAN.

Further, the WUR STA receiving the advertisement then may establish aBLE connection. The WLAN Association identifier may be included in theconnection in one example.

Once the STA has connected to the AP over BLE, they exchange informationsuch as power-save state information, WLAN link synchronizationinformation such as Beacon timing, and further may exchange signalinginformation to indicate when traffic is buffered for the STA on the WLANnetwork.

The GATT profile defined above may either be newly created or may use anexisting GATT profile. For example, the any of the following GATTprofiles may be used.

A first GATT profile that may be used is the Alert Notification Service.In this case Alert notifications would be used to trigger WLAN radiodata exchanges. The AP sends an alert to the device when there is datato be received.

A further GATT profile that may be used is the Transport DiscoveryService. Attribute Protocol (ATT) Indication frames could be used totrigger notifications.

When data traffic exchange is required over the WLAN link, the AP sendsa notification to the WUR STA using BLE and the WUR STA wakes up on theWLAN radio to resume communications.

In one embodiment, the AP and WUR STA exchange the following informationover the BLE connection.

When the WUR STA connects to the AP, the AP sends a data frame at anegotiated interval. The AP includes the IEEE 802.11 TimingSynchronization Function (TSF) Timer value and the Beacon Offset in eachdata frame exchanged with the WUR STA. This allows the device to remainsynchronized with the BSS.

Further, at regular intervals, the WUR STA may send an indication of theIEEE 802.11 Sleep state. The indication can also be exchanged over theBLE regardless of the WLAN power save state, in order for the WUR STA tosynchronize its state with the AP. A new parameter can be defined whichcan transmit the current power safe state of the WUR STA and the AP.This parameter can have the values Sleep, Awake or Doze.

Further, at regular intervals, the WUR STA and the AP may exchange OSIlayer 2 or layer 3 related information such as ARP, mDNS packets amongother information to maintain the layer 2, layer 3 connectivity while inthe Sleep state using BLE.

When there is buffered traffic available for the WUR STA, the AP may seta buffered traffic field to a 1, for example, in one embodiment. Inother embodiments, there may be two values depending on whether thetraffic is latency sensitive or not.

The WUR STA uses the TSF Timer and Offset to align its wake up on theWLAN connection. The AP uses its Sleep state information to ensure thatthe WUR STA power save state is synchronized at the 802.11 layer.

The process of waking up on the WLAN typically involves turning on theWLAN radio hardware if it is able to power off and performing a CarrierSense Multiple Access (CSMA) channel check on the channel the AP isoperating on before it went to sleep. The STA would, in one embodiment,exit the Sleep state into a Doze state, and listen on the WLAN network.The STA could use information available in the Bluetooth Beacon topredict the next WLAN beacon transmission. The WUR STA may then transmita PS-Poll or QoS Null-data frame to the AP to indicate that it isavailable.

BSS Transition

When a WUR STA is moving in relation to the access point, at some pointit may move out of range of the access point. In prior solutions, thiswould mean dropping the connection and reestablishing a connection to anew access point based on discovery at the WLAN.

In accordance with the present embodiments, the WUR STA, when in theSleep state, may monitor the link quality of the BLE connection. Oncethe link quality of the BLE connection falls below a link qualitythreshold, the BLE client, which is the WUR STA, may then periodicallyscan for BLE beacons from other Access Points. If the WUR STA discoversa BLE beacon having a better signal quality than a threshold, the WURSTA may transition the WLAN radio from a Doze to an Awake state totrigger an IEEE 802.11 scan and perform BSS Discovery on the WLAN. TheWUR STA may then potentially perform a BSS Transition to the new AP.

To minimize the power consumption on the WLAN radio for the WUR STA, theBLE beacon information may include the AP BSSID, operating channelinformation, and potentially the SSID, Mobility Domain, and HomogeneousExtended Service Set Identifier (HESSID) to identify the network.

The above assumes that in a multi-AP network all of the APs aretransmitting a BLE beacon.

The WUR STA may signal to the current AP to indicate that it is in theprocess of transitioning to a target AP. The WUR STA and current APmaintain communications over the BLE connection while the WUR STA istransitioning to the target AP.

When the WUR STA selects the target AP, it resumes WLAN communication bytransitioning from the Sleep state to the Awake state, and associateswith the target AP. Once the WUR STA has successfully associated withthe target AP, it establishes a new BLE connection to the target AP, andit may drop its BLE connection to the current AP.

Regarding AP behavior, when a WUR BSS Transition is enabled, APs in amulti-AP network may advertise the WUR BSS Transition capabilities inWLAN Beacons. This could be done using an Extended Capability bit orcould be added to the Wake-up Radio Capabilities, as shown with regardto FIG. 6.

Specifically, as seen in FIG. 6, an octet 610 is provided for wake upradio capabilities. Specifically, as seen in FIG. 6, octet 610 includesa first bit 612 which indicates whether or not wake up radio is enabled.

A second bit 614 may indicate BLE beacon enabled.

A third bit 616 may indicate the AP Sleep state.

The next four bits may provide a field 618 showing the AP sleep statecount as described above with regard to FIG. 3.

The final bit may provide a WUR BSS transition field 620. Bit 620 may beused to indicate the transition capabilities. Specifically, WUR APs withthe BSS transition enabled continually transmit BLE beacons. The APs areconfigured so that their Bluetooth radio has roughly the same coveragepattern as the WLAN radio. This allows the WUR STA to discover new APswhile in its Sleep state.

Regarding the WUR station, while in its Sleep state it may both monitorthe BLE link to the current AP and periodically scan for discovery oftarget APs over the BLE medium. The WUR STA maintains a list ofcandidate target APs.

When the signal quality of the BLE link to the current AP falls andcauses a trigger condition to BSS transition, the WUR may select acandidate target AP based on BLE scan results. The station may wakeupthe IEEE 802.11 radio to verify the WLAN Received Signal StrengthIndication (RSSI) for the target AP.

The station then wakes up to the WLAN radio on the operating channelspecified in target AP BLE beacon and associates to the target AP.

The current AP, in one embodiment, may also suggest a candidate targetAP to the WUR STA. For example, this may be done by using a neighborreport transmission from the AP to the WUR STA.

During the process of association, the WUR STA may terminate its BLEconnection to the current AP. This could occur at any time during theassociation process with the target AP. Once the WUR STA hassuccessfully associated, it establishes a BLE connection with the targetAP as described above with regard to the BLE association.

As will be appreciated, the above provides for mobile devices or otherstations to optimize power consumption while minimizing communicationlatency. Specifically, BLE radio is significantly more power efficientthat WLAN radio but its use still provides for fast transition in to acommunications mode on the WLAN radio.

The above solution further provides for a wake up radio that could beused on hardware that exists in the field today.

The modules and devices, including the WUR STAs and access points,described above may be any computing device or network node. Onesimplified diagram of a computing device is shown with regard to FIG. 7.

In FIG. 7, device 710 includes a processor 720 and a communicationssubsystem 730, where the processor 720 and communications subsystem 730cooperate to perform the methods of the embodiments described above.

Processor 720 is configured to execute programmable logic, which may bestored, along with data, on device 710, and shown in the example of FIG.7 as memory 740. Memory 740 can be any tangible, non-transitory computerreadable storage medium. The computer readable storage medium may be atangible or in transitory/non-transitory medium such as optical (e.g.,CD, DVD, etc.), magnetic (e.g., tape), flash drive, hard drive, or othermemory known in the art.

Alternatively, or in addition to memory 740, device 710 may access dataor programmable logic from an external storage medium, for examplethrough communications subsystem 730.

Communications subsystem 730 allows device 710 to communicate with otherdevices or network elements. If device 710 is an access point orwireless station, communications subsystem 730 includes both a WLANradio and a low power radio such as BLE.

Communications between the various elements of device 710 may be throughan internal bus 760 in one embodiment. However, other forms ofcommunication are possible.

Further, if any of computing devices 110, 112, 114, 120, or 140 aremobile devices, one example device is described below with regard toFIG. 8.

Mobile device 800 may comprise a two-way wireless communication devicehaving voice or data communication capabilities or both. Mobile device800 generally has the capability to communicate with other computersystems on the Internet. Depending on the exact functionality provided,the mobile device may be referred to as a data messaging device, atwo-way pager, a wireless e-mail device, a cellular telephone with datamessaging capabilities, a wireless Internet appliance, a wirelessdevice, a user equipment, or a data communication device, as examples.

Where mobile device 800 is enabled for two-way communication, it mayincorporate a communication subsystem 811, including a receiver 812 anda transmitter 814, as well as associated components such as one or moreantenna elements 816 and 818, local oscillators (LOs) 813, and aprocessing module such as a digital signal processor (DSP) 820. As willbe apparent to those skilled in the field of communications, theparticular design of the communication subsystem 811 will be dependentupon the communication network in which the device is intended tooperate.

Network access requirements will also vary depending upon the type ofnetwork 819. In some networks network access is associated with asubscriber or user of mobile device 800. A mobile device may require aremovable user identity module (RUIM) or a subscriber identity module(SIM) card in order to operate on a network. The SIM/RUIM interface 844is normally similar to a card-slot into which a SIM/RUIM card can beinserted and ejected. The SIM/RUIM card can have memory and hold manykey configurations 851, and other information 853 such asidentification, and subscriber related information. Without a SIM card,the mobile device may still be capable of limited functionality,including placing an emergency call.

When required network registration or activation procedures have beencompleted, mobile device 800 may send and receive communication signalsover the network 819. As illustrated in FIG. 8, network 819 can includemultiple base stations communicating with the mobile device.

Signals received by antenna 816 through communication network 819 areinput to receiver 812, which may perform such common receiver functionsas signal amplification, frequency down conversion, filtering, channelselection and the like. Analog to digital (A/D) conversion of a receivedsignal allows more complex communication functions such as demodulationand decoding to be performed in the DSP 820. In a similar manner,signals to be transmitted are processed, including modulation andencoding for example, by DSP 820 and input to transmitter 814 fordigital to analog (D/A) conversion, frequency up conversion, filtering,amplification and transmission over the communication network 819 viaantenna 818. DSP 820 not only processes communication signals, but alsoprovides for receiver and transmitter control. For example, the gainsapplied to communication signals in receiver 812 and transmitter 814 maybe adaptively controlled through automatic gain control algorithmsimplemented in DSP 820.

Mobile device 800 generally includes a processor 838 which controls theoverall operation of the device. Communication functions, including dataand voice communications, are performed through communication subsystem811. Processor 838 also interacts with further device subsystems such asthe display 822, flash memory 824, random access memory (RAM) 826,auxiliary input/output (I/O) subsystems 828, serial port 830, one ormore keyboards or keypads 832, speaker 834, microphone 836, othercommunication subsystem 840 such as a short-range communicationssubsystem and any other device subsystems generally designated as 842.Serial port 830 could include a USB port or other port known to those inthe art.

Some of the subsystems shown in FIG. 8 perform communication-relatedfunctions, whereas other subsystems may provide “resident” or on-devicefunctions. Notably, some subsystems, such as keyboard 832 and display822, for example, may be used for both communication-related functions,such as entering a text message for transmission over a communicationnetwork, and device-resident functions such as a calculator or tasklist.

Operating system software used by the processor 838 may be stored in apersistent store such as flash memory 824, which may instead be aread-only memory (ROM) or similar storage element (not shown). Thoseskilled in the art will appreciate that the operating system, specificdevice applications, or parts thereof, may be temporarily loaded into avolatile memory such as RAM 826. Received communication signals may alsobe stored in RAM 826.

As shown, flash memory 824 can be segregated into different areas forboth computer programs 858 and program data storage 850, 852, 854 and856. These different storage types indicate that each program canallocate a portion of flash memory 824 for their own data storagerequirements. Processor 838, in addition to its operating systemfunctions, may enable execution of software applications on the mobiledevice. A predetermined set of applications that control basicoperations, including at least data and voice communication applicationsfor example, will normally be installed on mobile device 800 duringmanufacturing. Other applications could be installed subsequently ordynamically.

Applications and software may be stored on any computer readable storagemedium. The computer readable storage medium may be a tangible or intransitory/non-transitory medium such as optical (e.g., CD, DVD, etc.),magnetic (e.g., tape) or other memory known in the art.

One software application may be a personal information manager (PIM)application having the ability to organize and manage data itemsrelating to the user of the mobile device such as, but not limited to,e-mail, messages, calendar events, voice mails, appointments, and taskitems. Further applications, including productivity applications, socialmedia applications, games, among others, may also be loaded onto themobile device 800 through the network 819, an auxiliary I/O subsystem828, serial port 830, short-range communications subsystem 840 or anyother suitable subsystem 842, and installed by a user in the RAM 826 ora non-volatile store (not shown) for execution by the processor 838.Such flexibility in application installation increases the functionalityof the device and may provide enhanced on-device functions,communication-related functions, or both. A further software applicationwith higher privilege level includes a device administrator module asdescribed above.

In a data communication mode, a received signal such as a text messageor web page download will be processed by the communication subsystem811 and input to the processor 838, which may further process thereceived signal for output to the display 822, or alternatively to anauxiliary I/O device 828.

A user of mobile device 800 may also compose data items such as messagesfor example, using the keyboard 832, which may be a completealphanumeric keyboard or telephone-type keypad, either physical orvirtual, among others, in conjunction with the display 822 and possiblyan auxiliary I/O device 828. Such composed items may then be transmittedover a communication network through the communication subsystem 811.

Where voice communications are provided, overall operation of mobiledevice 800 is similar, except that received signals may typically beoutput to a speaker 834 and signals for transmission may be generated bya microphone 836. Alternative voice or audio I/O subsystems, such as avoice message recording subsystem, may also be implemented on mobiledevice 800. Although voice or audio signal output is preferablyaccomplished primarily through the speaker 834, display 822 may also beused to provide an indication of the identity of a calling party, theduration of a voice call, or other voice call related information forexample.

Serial port 830 in FIG. 8 may be implemented in a mobile device forwhich synchronization with a user's desktop computer (not shown) may bedesirable, but is an optional device component. Such a port 830 mayenable a user to set preferences through an external device or softwareapplication and may extend the capabilities of mobile device 800 byproviding for information or software downloads to mobile device 800other than through a wireless communication network. As will beappreciated by those skilled in the art, serial port 830 can further beused to connect the mobile device to a computer to act as a modem or forcharging a battery on the mobile device.

Other communications subsystems 840, such as a short-rangecommunications subsystem, is a further component which may provide forcommunication between mobile device 800 and different systems ordevices, which need not necessarily be similar devices. For example, thesubsystem 840 may include an infrared device and associated circuits andcomponents or a Bluetooth™ or Bluetooth™ Low Energy communication moduleto provide for communication with similarly enabled systems and devices.Subsystem 840 may further include non-cellular communications such asWiFi or WiMAX, or near field communications.

The embodiments described herein are examples of structures, systems ormethods having elements corresponding to elements of the techniques ofthis application. This written description may enable those skilled inthe art to make and use embodiments having alternative elements thatlikewise correspond to the elements of the techniques of thisapplication. The intended scope of the techniques of this applicationthus includes other structures, systems or methods that do not differfrom the techniques of this application as described herein, and furtherincludes other structures, systems or methods with insubstantialdifferences from the techniques of this application as described herein.

Example clauses may include:

AA. A method at an access point, the method comprising: transmitting,from the access point, a message, the message providing an indicationthat the access point supports out-of-band signaling; associating theaccess point with at least one wireless station over a first radiotechnology, the associating comprising receiving an indication that theat least one wireless station supports out-of-band signaling;establishing a connection with the at least one wireless station to theaccess point using a second radio technology; receiving an indicationthat the at least one wireless station is entering a sleep state for aradio using the first radio technology; receiving data for the at leastone wireless station; buffering the data; sending a wakeup trigger overthe connection using the second radio technology; receiving a signalover the first radio technology that the at least one wireless stationis awake; and sending the buffered data to the at least one wirelessstation using the first radio technology.

BB. The method of clause AA, further comprising sending beaconinformation for the first radio technology over the connection using thesecond radio technology.

CC. The method of clause AA, wherein the second radio access technologyis one of a Bluetooth™, a Bluetooth™ Low Energy and a ZigBee™ radioaccess technology.

DD. The method of clause AA, wherein the message from the access pointis an Institute for Electrical and Electronics Engineers (IEEE) 802.11management frame and indication being a wake up radio element within themanagement frame.

EE. The method of clause AA, wherein the wakeup trigger is at least oneof a control frame; a frame control field setting both the Power-save(PS) bit field and the More Data bit field to one in the same frame; amanagement frame; or a Quality of Service (QoS) Null data frame.

FF. The method of clause BB, wherein the beacon information includes oneor more of: an IEEE 802.11 Timing Synchronization Function (TSF) timer;a Beacon Offset; Address Resolution Protocol (ARP) information; ormulticast Domain Name System (mDNS) information.

GG. The method of clause AA, further comprising sending to the at leastone wireless station, over the connection, at least one candidate targetaccess point.

HH. The method of clause AA, further comprising: determining that allwireless stations associated with the access point support out-of-bandwakeup triggers; sending a group-addressed trigger frame to indicate theaccess point will enter a sleep state after a specified number of targetbeacon transmit times (TBTT); and after the specified number of targetbeacon transmit times (TBTT), entering the Sleep state.

II. An access point comprising: a processor; and a communicationssubsystem, wherein the access point is configured to: transmit amessage, the message providing an indication that the access pointsupports out-of-band signaling; associate the access point with at leastone wireless station over a first radio technology, the associatingcomprising receiving an indication that the at least one wirelessstation supports out-of-band signaling; establish a connection with theat least one wireless station to the access point using a second radiotechnology; receive an indication that the at least one wireless stationis entering a sleep state for a radio using the first radio technology;receive data for the at least one wireless station; buffer the data;send a wakeup trigger over the connection using the second radiotechnology; receive a signal over the first radio technology that the atleast one wireless station is awake; and send the buffered data to theat least one wireless station using the first radio technology.

JJ. The access point of clause II, wherein the access point is furtherconfigured to send beacon information for the first radio technologyover the connection using the second radio technology.

KK. The access point of clause II, wherein the second radio accesstechnology is one of a Bluetooth™, a Bluetooth™ Low Energy and a ZigBee™radio access technology.

LL. The access point of clause II, wherein the message from the accesspoint is an Institute for Electrical and Electronics Engineers (IEEE)802.11 management frame and indication being a wake up radio elementwithin the management frame.

MM. The access point of clause II, wherein the wakeup trigger is atleast one of a control frame; a frame control field setting both thePower-save (PS) bit field and the More Data bit field to one in the sameframe; a management frame; or a Quality of Service (QoS) Null dataframe.

NN. The access point of clause JJ, wherein the beacon informationincludes one or more of: an IEEE 802.11 Timing Synchronization Function(TSF) timer; a Beacon Offset; Address Resolution Protocol (ARP)information; or multicast Domain Name System (mDNS) information.

OO. The access point of clause II, wherein the access point is furtherconfigured to send to the at least one wireless station, over theconnection, at least one candidate target access point.

PP. The access point of clause II, wherein the access point is furtherconfigured to: determine that all wireless stations associated with theaccess point support out-of-band wakeup triggers; send a group-addressedtrigger frame to indicate the access point will enter a sleep stateafter a specified number of target beacon transmit times (TBTT); andafter the specified number of target beacon transmit times (TBTT), enterthe Sleep state.

QQ. A computer readable medium for storing program instructions, theprogram instructions, when executed by a processor of an access point,cause the access point to: transmit a message, the message providing anindication that the access point supports out-of-band signaling;associate the access point with at least one wireless station over afirst radio technology, the associating comprising receiving anindication that the at least one wireless station supports out-of-bandsignaling; establish a connection with the at least one wireless stationto the access point using a second radio technology; receive anindication that the at least one wireless station is entering a sleepstate for a radio using the first radio technology; receive data for theat least one wireless station; buffer the data; send a wakeup triggerover the connection using the second radio technology; receive a signalover the first radio technology that the at least one wireless stationis awake; and send the buffered data to the at least one wirelessstation using the first radio technology.

The invention claimed is:
 1. A method at an access point, the methodcomprising: transmitting, from the access point, a message, the messageproviding an indication that the access point supports out-of-bandsignaling; associating the access point with at least one wirelessstation over a first radio technology, the associating comprisingreceiving an indication that the at least one wireless station supportsout-of-band signaling over the first radio technology; establishing aconnection with the at least one wireless station to the access pointusing a second radio technology; receiving an indication that the atleast one wireless station is entering a sleep state for a radio usingthe first radio technology; receiving data for the at least one wirelessstation; buffering the data; sending a wakeup trigger over theconnection using the second radio technology; receiving a signal overthe first radio technology that the at least one wireless station isawake; and sending the buffered data to the at least one wirelessstation using the first radio technology; wherein the first radiotechnology and the second radio technology are distinct from each other.2. The method of claim 1, further comprising sending beacon informationfor the first radio technology over the connection using the secondradio technology.
 3. The method of claim 1, wherein the second radioaccess technology is one of a Bluetooth™, a Bluetooth™ Low Energy and aZigBee™ radio access technology.
 4. The method of claim 1, wherein themessage from the access point is an Institute for Electrical andElectronics Engineers (IEEE) 802.11 management frame and indicationbeing a wake up radio element within the management frame.
 5. The methodof claim 1, wherein the wakeup trigger is at least one of a controlframe; a frame control field setting both the Power-save (PS) bit fieldand the More Data bit field to one in the same frame; a managementframe; or a Quality of Service (QoS) Null data frame.
 6. The method ofclaim 2, wherein the beacon information includes one or more of: an IEEE802.11 Timing Synchronization Function (TSF) timer; a Beacon Offset;Address Resolution Protocol (ARP) information; or multicast Domain NameSystem (mDNS) information.
 7. The method of claim 1, further comprisingsending to the at least one wireless station, over the connection, atleast one candidate target access point.
 8. The method of claim 1,further comprising: determining that all wireless stations associatedwith the access point support out-of-band wakeup triggers; sending agroup-addressed trigger frame to indicate the access point will enter asleep state after a specified number of target beacon transmit times(TBTT); and after the specified number of target beacon transmit times(TBTT), entering the Sleep state.
 9. The method of claim 1, furthercomprising: determining that all serviced wireless stations serviced bythe access point are configured to support out-of-band signaling;signaling, using a group-addressed frame, the serviced wireless stationsthat the access point is transition to the sleep state; and entering thesleep state, wherein the sleep state comprises turning off a first radiofor the access point while leaving a radio for the out of band signalingcapable of receiving messages.
 10. An access point comprising: aprocessor; and a communications subsystem, wherein the access point isconfigured to: transmit a message, the message providing an indicationthat the access point supports out-of-band signaling; associate theaccess point with at least one wireless station over a first radiotechnology, the associating comprising receiving an indication that theat least one wireless station supports out-of-band signaling over thefirst radio technology; establish a connection with the at least onewireless station to the access point using a second radio technology;receive an indication that the at least one wireless station is enteringa sleep state for a radio using the first radio technology; receive datafor the at least one wireless station; buffer the data; send a wakeuptrigger over the connection using the second radio technology; receive asignal over the first radio technology that the at least one wirelessstation is awake; and send the buffered data to the at least onewireless station using the first radio technology; wherein the firstradio technology and the second radio technology are distinct from eachother.
 11. The access point of claim 10, wherein the access point isfurther configured to send beacon information for the first radiotechnology over the connection using the second radio technology. 12.The access point of claim 10, wherein the second radio access technologyis one of a Bluetooth™, a Bluetooth™ Low Energy and a ZigBee™ radioaccess technology.
 13. The access point of claim 10, wherein the messagefrom the access point is an Institute for Electrical and ElectronicsEngineers (IEEE) 802.11 management frame and indication being a wake upradio element within the management frame.
 14. The access point of claim10, wherein the wakeup trigger is at least one of a control frame; aframe control field setting both the Power-save (PS) bit field and theMore Data bit field to one in the same frame; a management frame; or aQuality of Service (QoS) Null data frame.
 15. The access point of claim11, wherein the beacon information includes one or more of: an IEEE802.11 Timing Synchronization Function (TSF) timer; a Beacon Offset;Address Resolution Protocol (ARP) information; or multicast Domain NameSystem (mDNS) information.
 16. The access point of claim 10, wherein theaccess point is further configured to send to the at least one wirelessstation, over the connection, at least one candidate target accesspoint.
 17. The access point of claim 10, wherein the access point isfurther configured to: determine that all wireless stations associatedwith the access point support out-of-band wakeup triggers; send agroup-addressed trigger frame to indicate the access point will enter asleep state after a specified number of target beacon transmit times(TBTT); and after the specified number of target beacon transmit times(TBTT), enter the Sleep state.
 18. The access point of claim 10, whereinthe access point is further configured to: determine that all servicedwireless stations serviced by the access point are configured to supportout-of-band signaling; signal, using a group-addressed frame, theserviced wireless stations that the access point is transition to thesleep state; and enter the sleep state, wherein the sleep statecomprises turning off a first radio for the access point while leaving aradio for the out of band signaling capable of receiving messages.
 19. Anon-transitory computer readable medium for storing programinstructions, the program instructions, when executed by a processor ofan access point, cause the access point to: transmit a message, themessage providing an indication that the access point supportsout-of-band signaling; associate the access point with at least onewireless station over a first radio technology, the associatingcomprising receiving an indication that the at least one wirelessstation supports out-of-band signaling over the first radio technology;establish a connection with the at least one wireless station to theaccess point using a second radio technology; receive an indication thatthe at least one wireless station is entering a sleep state for a radiousing the first radio technology; receive data for the at least onewireless station; buffer the data; send a wakeup trigger over theconnection using the second radio technology; receive a signal over thefirst radio technology that the at least one wireless station is awake;and send the buffered data to the at least one wireless station usingthe first radio technology; wherein the first radio technology and thesecond radio technology are distinct from each other.